Vena cava filter formed from a sheet

ABSTRACT

A filter formed from a sheet is described herein. In one aspect of the invention, a filter is formed from a sheet of material and, following removal of portions of the sheet, the filter is folded into a shape for insertion into a blood vessel. In another aspect of the invention, features for a filter are formed from a sheet of material and incorporated into the filter.

PRIORITY

This application claims the benefit of priority to U.S. ProvisionalPatent Application No. 60/796,650, filed May 2, 2006, which isincorporated by reference into this application as if fully set forthherein.

BACKGROUND OF THE INVENTION

Inferior vena cava (IVC) filters are devices configured for insertioninto a blood vessel to capture particles that may be present in theblood stream which, if transported to, for example, the lungs couldresult in serious complications and even death. Typically, IVC filtersare utilized in patients who have a contraindication to anticoagulationor in patients developing clinically apparent deep vein thrombosis (DVT)and/or pulmonary embolism (PE). Patients who have recently suffered fromtrauma, have experienced a heart attack (myocardial infarction), or whohave undergone major surgical procedure (e.g., surgical repair of afractured hip, etc.) may develop clinically apparent DVT. When athrombus clot loosens from the site of formation and travels to thelung, it may cause PE, a life-threatening condition. An IVC filter maybe placed in the circulatory system to intercept one or more clots andprevent them from entering the lungs. IVC filters are either permanentor retrievable.

There are many different configurations for IVC filters, including thosethat include a central hub from which extend a plurality of struts thatform filter baskets having a conical configuration, such as disclosed inU.S. Pat. No. 6,258,026, which is incorporated by reference in itsentirety into this application. Other IVC filter configurations utilizewires and/or frame members to form straining devices that permit flow ofblood while trapping larger particles. IVC filters are generallyconfigured for compression into a small size to facilitate delivery intothe inferior vena cava and subsequent expansion into contact with theinner wall thereof. The IVC filter may later be retrieved from thedeployed site by compressing the legs, frame members, etc., depending onthe filter configuration. Typically, an IVC filter will include hooks oranchoring members for anchoring the filter in position within theinferior vena cava. The hooks may be more elastic than the legs or framemembers to permit the hooks to straighten in response to withdrawalforces, which facilitate withdrawal from the endothelium layer of theblood vessel without risk of significant injury to the vessel wall.

The following references relate to blood vessel filters: U.S. Pat. No.3,540,431; U.S. Pat. No. 4,793,348; U.S. Pat. No. 6,506,205; U.S. Pat.No. 6,551,342; U.S. Pat. No. 6,712,834; U.S. Pat. No. 6,783,538; U.S.Pat. No. 6,881,218; U.S. Pat. Application Publication No. 2004/0073252;U.S. Patent Application Publication No. 2004/0087999; and U.S. PatentApplication Publication No. 2005/0080449, each of which is incorporatedby reference in its entirety into this application.

Applicants have recognized that it would be desirable to form an IVCfilter from a sheet of material, including forming an IVC filter from asheet and incorporating filter features formed from a sheet into an IVCfilter. Thus, described herein are embodiments of an IVC filter formedfrom a sheet.

BRIEF SUMMARY OF THE INVENTION

Accordingly, implantable medical devices, including IVC filters that areformed from a sheet are described herein. In one embodiment, a filterfor placement in a blood vessel includes a body defining a longitudinalaxis, the body having a generally planar surface extending generallyparallel to the longitudinal axis, and a plurality of appendagesextending away from the longitudinal axis, at least one of the pluralityof appendages having a generally planar surface.

In another embodiment, a filter includes a longitudinal body including aproximal section having a first cross-sectional area, a distal sectionhaving a second cross-sectional area, and a joining section positionedbetween the proximal and distal sections having a third cross-sectionalarea less than both the first and second cross-sectional areas, and aplurality of appendages having a proximal end joined to a hub such thatthe appendages in a non-stressed position lie in a plane generallyoblique to the longitudinal body, the hub including an openingconfigured for movement along a length of the joining section.

In yet another embodiment, a filter includes a longitudinal body havinga first cross-sectional area, a first stop member spaced apart from asecond stop member, the first and second stop members having a secondcross-sectional area larger than the first cross-sectional area, and aplurality of appendages having a proximal end joined to a hub such thatthe appendages in a non-stressed position lie in a plane generallyoblique to the longitudinal body, the hub including an openingconfigured for movement along a length of the body between the stopmembers.

In still another embodiment, a filter includes a longitudinal bodyincluding a proximal section, an intermediate section, and a distalsection, a first joining section positioned between the proximal sectionand the intermediate section and a second joining section positionedbetween the intermediate section and the distal section, the first andsecond joining sections each having a cross-sectional area less than across-sectional area of the proximal section, the intermediate sectionand the distal section, a first set of appendages having a proximal endjoined to a first hub such that the appendages in a non-stressedposition lie in a plane generally oblique to the longitudinal body, thefirst hub positioned along the first joining section and including anopening configured for movement along a length of the first joiningsection, and a second set of appendages having a proximal end joined toa second hub such that the appendages in a non-stressed position lie ina plane generally oblique to the longitudinal body, the second hubpositioned along the second joining section and including an openingconfigured for movement along a length of the second joining section.

In yet another embodiment, a filter includes a longitudinal body havinga first cross-sectional area, a first stop member spaced apart from asecond stop member, the first and second stop members having a secondcross-sectional area larger than the first cross-sectional area, a thirdstop member spaced apart from a fourth stop member, the third and fourthstop members having a third cross-sectional area larger than the firstcross-sectional area, a first set of appendages having a proximal endjoined to a first hub such that the appendages in a non-stressedposition lie in a plane generally oblique to the longitudinal body, thefirst hub including an opening configured for movement along a length ofthe body between the first and second stop members, and a second set ofappendages having a proximal end joined to a second hub such that theappendages in a non-stressed position lie in a plane generally obliqueto the longitudinal body, the second hub including an opening configuredfor movement along a length of the body between the third and fourthstop members.

In one embodiment, a method of making a filter includes removingportions of a sheet of material along a first set of predetermined linesto form a plurality of arms, a plurality of legs and a body, folding thesheet of material along a second set of predetermined lines such thatthe arms and legs extend radially outward from the body along alongitudinal axis, and connecting a first joining section to a secondjoining section.

These and other embodiments, features and advantages will become moreapparent to those skilled in the art when taken with reference to thefollowing more detailed description of the invention in conjunction withthe accompanying drawings that are first briefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view of a filter pattern following removal ofportions of a sheet from which the filter was formed.

FIG. 1B is a perspective view of the filter pattern of FIG. 1 assembledinto a filter for insertion into a blood vessel.

FIG. 2A is a perspective view of one embodiment of a filter.

FIG. 2B is an enlarged view of the section 2B-2B of FIG. 2A.

FIG. 2C ₁ is a side view of the filter of FIG. 2A being delivered to avessel, while FIG. 2C ₂ is a side view of the filter of FIG. 2A beingrecovered from a vessel.

FIG. 2D is an enlarged view of one embodiment of a distal end of anappendage of FIG. 2A.

FIG. 2E is an enlarged view of another embodiment of a distal end of anappendage of FIG. 2A.

FIG. 2F is an enlarged view of yet another embodiment of a distal end ofan appendage of FIG. 2A.

FIG. 2G is an enlarged view of still another embodiment of a distal endof an appendage of FIG. 2A.

FIG. 3A is a full perspective view of an embodiment of a filter.

FIG. 3B is a perspective view of the filter of FIG. 3A in a deliveryconfiguration.

FIG. 4 is a perspective view of another embodiment of a filter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are identicallynumbered. The drawings, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. The detailed description illustrates by way of example, notby way of limitation, the principles of the invention. This descriptionwill clearly enable one skilled in the art to make and use theinvention, and describes several embodiments, adaptations, variations,alternatives and uses of the invention, including what is presentlybelieved to be the best mode of carrying out the invention.

While the examples provided herein are discussed with respect to IVCfilters, it should be appreciated that the filter embodiments describedherein could be used for filter applications that do not involve placinga filter device in the inferior vena cava. In other words, the filtersdescribed herein are not limited to IVC applications. Moreover, as usedherein, the term “suture material” means a material that is, or couldbe, used as a suture thread by a surgeon, and which material may beresorbable in situ. Such material may include, for example, syntheticpolymers, polyglycolic acid (PGA), polylactic acid (PLA), polydioxanone(PDS), polyglactin, nylon, polypropylene (prolene), silk, catgut,non-absorbable/non-biodegradable materials, and combinations thereof.Included in this term are both monofilament and multifilament suturematerials.

Further, as used herein the term “bio-resorbable” includes a suitablebiocompatible material, mixture of various biocompatible materials orpartial components of biocompatible material being altered into othermaterials by an agent present in the environment (e.g., a biodegradablematerial that degrades via a suitable mechanism such as hydrolysis whenplaced in biological tissue); such materials being removed by cellularactivity or incorporated into the cellular structure (i.e.,bioresorption, bioresorping, bioabsorption, or bioresorbable), suchmaterials being degraded by bulk or surface degradation (i.e.,bioerosion such as, for example, a water insoluble polymer that turnswater-soluble in contact with biological tissue or fluid), or suchmaterials being altered by a combination of one or more ofbiodegradable, bioerodable or bioresorbable activity when placed incontact with biological tissue or fluid.

As used herein, the terms “weaken” and “weakening” mean making a sectionor sections of the filter thinner, heat treating the section orsections, cutting grooves into the section or sections, etc. Further, asused herein, the term “lower material strength” means either a lowermodulus of elasticity or a lower ability to resist bending. Also, asused herein, the term “hook” means a member configured to engage a bloodvessel wall, examples of which are provided in U.S. Pat. No. 6,258,026,which is incorporated by reference in its entirety into thisapplication. Possible materials for the sheet and filter describedherein include a suitable biocompatible material such as, for example,stainless steel, noble metals and their alloys, shape memory metals,shape memory alloys, super elastic metal, super elastic shape memorymaterials, shape memory metal alloys, linear elastic shape memory metal,metal alloys, shape memory polymers, polymers, bio-materials (e.g.,metal alloys such as those shown and described in U.S. Pat. No.6,287,332 and U.S. Patent Application Publication No. 2002/0004060, eachof which is incorporated by reference in its entirety into thisapplication), and combinations thereof.

Where the filter is to be utilized with bio-active agents to control theformation of emboli, bio-active agents can be coated to a portion or theentirety of the filter for controlled release of the agents once thefilter is implanted. The bio-active agents can include, but are notlimited to, vasodilator, anti-coagulants, such as, for example, warfarinand heparin. Other bio-active agents can include, but are not limitedto, agents such as, for example, anti-proliferative/antimitotic agentsincluding natural products such as vinca alkaloids (i.e. vinblastine,vincristine, and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e.etoposide, teniposide), antibiotics (dactinomycin (actinomycin D)daunorubicin, doxorubicin and idarubicin), anthracyclines, mitoxantrone,bleomycins, plicamycin (mithramycin) and mitomycin, enzymes(L-asparaginase which systemically metabolizes L-asparagine and deprivescells which do not have the capacity to synthesize their ownasparagine); antiplatelet agents such as G(GP) II_(b)/III_(a) inhibitorsand vitronectin receptor antagonists; anti-proliferative/antimitoticalkylating agents such as nitrogen mustards (mechlorethamine,cyclophosphamide and analogs, melphalan, chlorambucil), ethyleniminesand methylmelamines (hexamethylmelamine and thiotepa), alkylsulfonates-busulfan, nirtosoureas (carmustine (BCNU) and analogs,streptozocin), trazenes-dacarbazinine (DTIC);anti-proliferative/antimitotic antimetabolites such as folic acidanalogs (methotrexate), pyrimidine analogs (fluorouracil, floxuridine,and cytarabine), purine analogs and related inhibitors (mercaptopurine,thioguanine, pentostatin and 2-chlorodeoxyadenosine {cladribine});platinum coordination complexes (cisplatin, carboplatin), procarbazine,hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen);anti-coagulants (heparin, synthetic heparin salts and other inhibitorsof thrombin); fibrinolytic agents (such as tissue plasminogen activator,streptokinase and urokinase), aspirin, dipyridamole, ticlopidine,clopidogrel, abciximab; antimigratory; antisecretory (breveldin);anti-inflammatory: such as adrenocortical steroids (cortisol, cortisone,fludrocortisone, prednisone, prednisolone, 6α-methylprednisolone,triamcinolone, betamethasone, and dexamethasone), non-steroidal agents(salicylic acid derivatives i.e. aspirin; para-aminophenol derivativesi.e. acetominophen; indole and indene acetic acids (indomethacin,sulindac, and etodalac), heteroaryl acetic acids (tolmetin, diclofenac,and ketorolac), arylpropionic acids (ibuprofen and derivatives),anthranilic acids (mefenamic acid, and meclofenamic acid), enolic acids(piroxicam, tenoxicam, phenylbutazone, and oxyphenthatrazone),nabumetone, gold compounds (auranofin, aurothioglucose, gold sodiumthiomalate); immunosuppressives: (cyclosporine, tacrolimus (FK-506),sirolimus (rapamycin), azathioprine, mycophenolate mofetil); angiogenicagents: vascular endothelial growth factor (VEGF), fibroblast growthfactor (FGF); angiotensin receptor blockers; nitric oxide donors;anti-sense oligionucleotides and combinations thereof; cell cycleinhibitors, mTOR inhibitors, and growth factor receptor signaltransduction kinase inhibitors; retenoids; cyclin/CDK inhibitors; HMGco-enzyme reductase inhibitors (statins); and protease inhibitors.

Referring now to FIG. 1A, a filter 110 is shown, following removal ofportions of a sheet from which the filter 110 was formed but prior tothe filter 110 being assembled into a device for deployment within ablood vessel. The filter 110 may be cut from a sheet of material bylaser or other techniques known to one skilled in the art. The patternfor the filter 110 may be pre-programmed into a laser device or othercutting device, such that all features of the filter 110 are formed fromthe same sheet. Alternatively, select features of the filter (e.g., armsor other appendages) may be separately formed and attached to a filterframework formed from a sheet of material. The sheet of materialutilized for forming the filter 110 may be any of the materialsdiscussed above, but in one preferred embodiment, the material isNitinol. The filter 110 includes arms 112 and legs 114 that arealternating from a first side 122 of the pre-assembled filter 110 to asecond side 124, such that there are a total number of eleven appendages(six arms 112 and five legs 114). While it should be appreciated thatany number of appendages is possible and within the scope of theinvention, the preferred number of appendages is between 4 and 12.

In the embodiment shown in FIG. 1A, the method of making a filterincludes removing portions of a sheet of material along a first set ofpredetermined lines to form a plurality of arms, a plurality of legs anda body, folding the sheet of material along a second set ofpredetermined lines such that the arms and legs extend radially outwardfrom the body along a longitudinal axis, and connecting a first joiningsection to a second joining section. In particular, a central member orbody 126 includes a leg 114 extending distally from a retrieval member118, which is positioned at a proximal end of the filter 110. Theconfiguration and number of the arms 112 and legs 114 extending from thecentral member 126 to the first side 122 are the same as theconfiguration and number of the arms 112 and legs 114 extending from thecentral member 126 to the second side 124; however, other embodimentsmay include non-symmetrical configurations. The central member 126defines a longitudinal axis L of the filter 110 and has a generallyplanar surface 130 extending generally parallel to the longitudinal axisL. The arms 112 and legs 114 also have generally planar surfaces asfilter 110 is formed from a sheet of material. In other embodiments, atleast one of the appendages of the filter has a generally planarsurface. The cross-section of the central member 126, the arms 112 andthe legs 114 in filter 110 is generally rectangular, although in otherembodiments, the cross-section may be generally square. Although each ofthe appendages of filter 110 is shown with similar cross-sections, inother embodiments, one or more of the appendages and/or body may beconstructed with different cross-sectional shapes. For example, byvarying the width of the body, arms and/or legs, a sheet of materialwith uniform thickness could result in different cross-sectional shapesfor the body and/or appendages. Alternatively, the widths of the body,arms and legs may be generally equivalent, such as in FIG. 1A, but thesheet of material may have regions of varying thickness to producedifferent cross-sectional shapes for the body and/or appendages.

The legs 114 in filter 110 are configured with pointed tips 116 forformation of anchoring members, such as hooks, in a secondary procedure,while the arms 112 have blunt or rounded distal ends. In otherembodiments, the arms 112 may include pointed tips. There are variouspossibilities for the configuration of the pointed tips 116, some ofwhich are shown in FIGS. 2D-2G, discussed below. As indicated in FIG.lA, the filter 110 may include fold lines 128 that extend alongpre-determined paths to delineate the arms 112 and legs 114. These foldlines may be etched onto the filter pattern or may otherwise beindicated. In one embodiment, a secondary procedure may be utilized toweaken the sheet of material along certain paths, such as the fold lines128, in order to facilitate folding of the filter 110.

Once pre-programmed cuts have been made in a sheet of material, portionsare removed so that a pre-determined filter configuration remains. Priorto, or following removal of, the portions of the sheet, one or moresecondary procedures may be implemented. One potential secondaryprocedure involves weakening a section of one or more of the appendagesof a filter. For example, in the embodiment shown in FIG. 1, the legs114 are formed with a pointed tip section 116 at the distal end thereof.Thus, in one embodiment, a weakening procedure is performed in which asection proximal the tip section is thinned, removed, grooved, heated,etc. in order to lower material strength of the section such thatbending the tip section is facilitated. The bent tip section can form ahook for engagement of a blood vessel wall, such as shown in FIG. 1B.Weakening procedures can also be performed on areas of the filter otherthan the tip section of an appendage. Another potential secondaryprocedure involves treating, such as heat setting, certain features ofthe filter to form the features into a desired configuration. Otherpotential secondary procedures include, for example, heat setting thefilter in a collapsed or expanded configuration, heat treating sectionsof the filter, performing surface treatments on sections of the filter,performing chemical treatments on sections of the filter, and coatingone or more surfaces of the filter with one or more bio-active agents.In one preferred embodiment, an anti-coagulant bio-active agent isdisposed on a surface of the filter 112. The anti-coagulant agent may bereleased into the blood stream via various mechanisms, as known to oneskilled in the art, upon implantation and deployment of the filter in ablood vessel. One technique for controlled release of bio-active agentscan be achieved by dispersing the bio-active agents within a porouspolymer medium for elution of the agents.

Referring to FIG. 1B, the filter 110 has been assembled from a planarpattern shown in FIG. 1A to a shape for implantation in a blood vessel.The filter 110 is folded along fold lines 128 and joined along selectsections by methods known to one skilled in the art, including, forexample, welding, adhesive bonding, solvent bonding, etc. In theembodiment of FIG. 1B, the arms 112 and legs 116 are folded so that theyextend radially outward from central member 126 in an expandedconfiguration; to aid in this formation, the arms 112 and legs 116 maybe treated by one or more secondary processes, such as those discussedabove. Following the preferred arrangement of the arms 112 and legs 116with respect to central member 126, a joining section 120 is formedthrough welding. The joining section in the embodiment of FIG. 1Aincludes proximal portions of opposing arms 112 adjacent the centralmember 128. Other joining sections may also be formed at differentpoints along the filter 110. In one embodiment, a tube or solid tip maybe utilized along with an attachment procedure, such as welding, inorder to maintain the filter in its expanded configuration when subjectto blood vessel pressures.

Also, as discussed above, the pointed tips 116 in FIG. 1A may be formedinto anchor members, such as hooks, configured for engagement with ablood vessel wall. Alternatively, legs 114 may be formed with endsconfigured for attachment of separately formed hooks. For example, thedistal end of one or more legs may contain a notch or area formed toreceive a proximal section of a separately formed hook. In such anembodiment, the hook(s) may be attached to the end of the one or morelegs 114 in a secondary procedure by methods known to one skilled in theart (e.g., welding, adhesive bonding, solvent bonding, etc.). In oneembodiment, the hook (whether separately formed or integral with the leg114) contains a linear portion connected to an arcuate portion thatterminates in a point, as shown and described in U.S. Pat. No.6,258,026. In one embodiment, the arcuate member has a cross-sectionalarea less than the cross-sectional area of the linear portion, as shownand described in U.S. Pat. No. 6,258,026. Details of potential hooks forlegs 114 are shown and described in U.S. patent application Ser. No.11/429,975, filed May 9, 2006, claiming priority to U.S. ProvisionalPatent Application No. 60/680,601, filed May 12, 2005, each of which isincorporated by reference in its entirety into this application.

The filter 10 is illustrated in FIG. 1B in an expanded configuration,defining an expanded perimeter. For delivery of the filter 110 to ablood vessel, the filter 110 is compressed to a collapsed configuration,defining a collapsed perimeter smaller than the expanded perimeter. Thefilter 110 can be self-expanding due an intrinsic characteristic of thematerial of the sheet from which it is formed, in which case deploymentmay involve simply removal of a constraining force or exposing thefilter to an elevated temperature (e.g., for a filter employing atemperature sensitive material), or alternatively can require a separateexpansion agent (e.g., balloon) for expansion. It should be appreciatedthat while the filter 110 may be of the self-expanding variety, aseparate expansion agent may also be utilized for deployment within ablood vessel. Retention members (e.g., hooks or barbs) may be providedon arms or legs such as the retention members shown and described inU.S. Pat. Nos. 6,517,573 and 6,443,972, each of which is incorporated byreference in its entirety into this application. Arms 112 may beprovided with additional bend to assist in centering the filter.

FIG. 2A illustrates filter 10, in which an appendage member 20 is formedfrom a sheet of material, while other portions of the filter, includingbody 11 are formed from a rod or structure with a lumen. Materials forthe sheet, rod and structure with a lumen are described above withrespect to the sheet and filter materials, but in a preferred embodimentthe material for each is Nitinol. The body 11 includes a proximalsection 12 and a distal section 14 joined by a joining section 16. Thesesections may be formed from one or more solid rods, hollow structures,or combinations thereof. In one embodiment, one or more portions of asolid rod or hollow structure may include a lumen, defined by a wall.The wall may be porous, including one or more openings, such that one ormore bioactive agents disposed within the lumen may be released into theblood vessel into which the filter 10 is deployed.

The body 11 may have a circular or non-circular cross-section (e.g.,square, rectangle, triangle, oval, etc.), but in a preferred embodimentthe body 11 is generally tubular with a generally circularcross-section. Also, the different sections of the body may havedifferent cross-sectional shapes and sizes. For example, the proximalsection 12 may have a cross-sectional area smaller or larger than thecross-sectional area of the distal section 14, the joining section 16could have a square cross-section while the proximal and distal sections12, 14 have circular cross-sections, etc. However, in a preferredembodiment, the cross-sectional shapes of each of the proximal, distaland joining sections is circular; the cross-sectional areas of theproximal and distal sections are approximately equivalent; and thecross-sectional area of the joining section is less than thecross-sectional area of the proximal section and the distal section.Moreover, the proximal and distal sections may have approximately thesame length or different lengths. In one embodiment, the distal section14 has a length greater than the length of the proximal section 12.Attached to the proximal section 12 (or integral therewith) is aretrieval member 18, shown exemplarily in a hook-like configuration.Attachment of retrieval member 18 to the proximal section 12 may beaccomplished by methods known to one skilled in the art (e.g., welding,adhesive bonding, solvent bonding, etc.). In one embodiment, theproximal section 12, distal section 14, joining section 16 and retrievalmember 18 are formed from a single generally tubular solid rod in thesame manner as described above or alternatively, the joining section 16is formed by removing portions of the rod and the retrieval member 18 isformed through heating and molding processes or via machining (e.g.,EDM) and deburring/polishing. The retrieval member 18 can be pre-cut orattached to the filter and then bent into its final configuration.

The length of the joining section 16 is established based on the desiredlength for movement of the appendage member 20, which includes a set ofappendages 22. In a preferred embodiment, the joining section 16 has alength between approximately 0.1 mm and approximately 40 mm, preferablybetween approximately 0.1 mm and approximately 3 mm. Each appendage 22is attached at its proximal end to a hub 24, which can be configured forsliding movement along the length of the joining section 16 to relievestress or strain on the filter. As shown in FIG. 2B, the hub 24 has anopening 26 that has a shape similar to that of the joining section 16with a slightly larger size than the circumference of the joiningsection 16 to permit movement. In one embodiment, the opening 26 may beconfigured to have substantially the same cross-sectional area as thejoining section 16 such that a friction fit between the two isestablished in order to prevent unimpeded movement of the hub 24 alongthe length of the joining section 16. In another embodiment, the opening26 may be configured with a larger cross-sectional area than the joiningsection 16 to facilitate movement of the hub 24 along the length of thejoining section 16. In either embodiment, the opening has a smallercross-sectional area than both the proximal section 12 and distalsection 14 such that movement outside of the length of the joiningsection 16 is prevented. In an embodiment where the proximal section anddistal section are tubular, the opening has a diameter less than thediameter of the proximal and distal sections.

In a preferred embodiment, the appendages and hub are formed from asingle sheet of material, having portions removed from a pre-determinedpattern programmed into a cutting device, such as a laser device. Thethickness of the sheet in a preferred embodiment is betweenapproximately 0.1 mm and 0.4 mm. The appendages 22, thus, have opposingplanar surfaces and lie in substantially the same plane in anon-stressed position. The appendages lie in a plane approximatelyperpendicular and preferably in a plane generally oblique to the body 11in a non-stressed position. Alternatively, the appendages can be heattreated and mechanically formed to form various angles. Although anynumber of appendages 22 is possible for the appendage member 20, in apreferred embodiment, the appendage member 20 includes between 4 and 12appendages 22. The appendages 22 may be of varying thickness along theirlength, which may be produced by a sheet of material with varyingthickness or through the utilization of secondary procedures. Theappendages 22 may also be of varying width along their length (e.g.,tapered from the proximal end to the distal end, shown in FIGS. 2D-2E).Moreover, the thickness or width of the appendages 22 may differ in agiven set of appendages. For example, in one embodiment, alternatingappendages in the set of appendages may have a similar thickness, whichthickness is greater than adjacent appendages. In a preferredembodiment, the hub 24 can be connected to the body 16 by coupling thehub 24 onto the body 16 prior to the placement of the retrieval member12. The coupling of the hub 24 can be achieved by a suitable couplingtechnique such as, for example, welding or screw threads.

The thickness and configuration of the appendages 22 in a preferredembodiment is such that the appendages are bendable in both a proximaland distal direction. More specifically, with reference to FIG. 2A, theappendages 22 can be fashioned with a flexibility in which the distalends of the appendages 22 can bend in a direction toward and away fromthe retrieval member 18 such that at least the distal ends of theappendages 22 are generally parallel to the body 11. By imparting suchflexibility to the appendages, recovery and delivery of the filter 10can be accomplished using either a jugular access site or a femoralaccess site, as shown in FIG. 2C ₁, which illustrates a filter delivery,and FIG. 2C ₂, which illustrates a filter recovery, thereby increasingthe options available to a clinician. Thus, a force (e.g., catheter 100)contacting the appendages 22 directed in a distal direction from aproximal direction (i.e., from a jugular access site) will cause theappendages 22 to bend in a distal direction, while a force contactingthe appendages 22 directed in a proximal direction from a distaldirection (i.e., from a femoral access site) will cause the appendages22 to bend in a proximal direction.

The distal ends of the appendages 22 can be orthogonal, as shown in FIG.2A, or can be configured to terminate in a point. Examples of distal endsections for appendages 22 are shown in FIGS. 2D-2G. It should beappreciated that these examples are non-limiting and are non-exclusiveto a particular set of appendages; that is, one set of appendages mayinclude one or more of the distal end sections shown in FIGS. 2D-2G.Referring to FIGS. 2D-2E, the width of the appendage 22 tapers from aproximal portion of the appendage to the distal end as discussed above;however, the distal end of the appendage 22 in FIG. 2E terminates in apoint 21, while the distal end of the appendage 22 in FIG. 2D isgenerally flat (i.e., the distal section is generally trapezoid inconfigured). FIG. 2F shows a distal end 23 that tapers to a point,although the sides of the majority of the length of the appendage 22 areparallel. Finally, FIG. 2G illustrates a hook 25 on the distal end of atapered portion of the appendage 22, the hook 25 having a curved section27 with a cross-sectional area less than a cross-sectional area of ashaft section 29. As discussed above, the hook may be formed bysecondary procedures following formation of the appendage member 20.Also contemplated herein are distal ends of appendages that have roundededges. The examples shown in FIGS. 2D-2G and described may be utilizedwith any of the appendages of the embodiments discussed herein.Retention members (e.g., hooks or barbs) may be provided on arms or legssuch as the retention members shown and described in U.S. Pat. Nos.6,517,573 and 6,443,972, each of which is incorporated by reference inits entirety into this application.

Referring now to FIG. 3A, a filter 30 is illustrated, including a body31, a first appendage member 50 and a second appendage member 60. Bothfirst and second appendage members 50, 60 may be configured according toany of the embodiments discussed above in connection with appendagemember 20 of FIG. 2A. Body 31 includes a proximal section 32, anintermediate section 34 and a distal section 36. Proximal section 32 isconnected to intermediate section 34 by a first joining section 42 andintermediate section 34 is connected to distal section 36 by a secondjoining section 44. Attached to (or integral with) proximal section 32and distal section 36, respectively, are first retrieval member 38 andsecond retrieval member 40. First appendage member 50 includes a firstset of appendages 52 attached at their proximal end to a first hub 54,while second appendage member 60 includes a second set of appendages 62attached at their proximal end to a second hub 64. As with theembodiment of FIG. 2A, the first and second hubs 54, 64 are configuredto move along the length of first and second joining sections 42, 44,respectively. Filter 30, by including retrieval members at each end ofthereof, facilitates recovery or delivery thererof because either ajugular or femoral approach may be utilized with a snare. The snare ismovable through a retrieval catheter and is configured to engage theretrieval members 38, 40 such that either approach may be employed by aclinician to recover the filter 30 from a blood vessel in which it isdeployed. As described above, the appendages 52 and 62 may be configuredto flexibly bend when contacted with a force during recovery, such thatthe appendages 52 and 62 bend in the same direction as the contactingforce of the catheter as shown in FIG. 2C ₂.

FIG. 3B shows one potential configuration of appendages 52 and 62,following a secondary procedure, e.g., a loading or a deployedconfiguration. In particular, each of the first and second appendagemembers 50, 60 are arranged so that they form a conical shape by methodsknown to one skilled in the art, such as annealing. As shown, the firstset of appendages 52 have distal ends directed toward the retrievalmember 38 positioned at the proximal end of the filter 30, while thesecond set of appendages 62 have distal ends directed toward theretrieval member 40 positioned at the distal end of the filter 40. Thus,the first and second appendage members 50, 60 form conical basketsdirected in generally opposite directions. In another embodiment, thefirst and second appendage members 50, 60 are directed in the samedirection (either toward the proximal or distal end). With respect tomaterials, in the preferred embodiments, the entire filter can beresorbed or portions of the filter can be resorbed over time. Retentionmembers (e.g., hooks or barbs) may be provided on arms or legs such asthe retention members shown and described in U.S. Pat. Nos. 6,517,573and 6,443,972, each of which is incorporated by reference in itsentirety into this application.

FIG. 4 illustrates filter 70 including a body 72 and an appendage member80. Appendage member 80 includes a set of appendages 82 attached attheir proximal end to a hub 84. In this embodiment, hub 84 is limited inits movement by first and second stop members 74, 76 attached to thebody 72. The first and second stop members 74, 76 have a greatercross-sectional area than the opening of the hub 84 to prevent movementof the hub beyond the length between the first and second stop members74, 76, which in a preferred embodiment is between approximately 0.5 mmand approximately 40 mm. The body 72 may have any cross-sectional shape,as discussed above, but in a preferred embodiment is circular. Insteadof two stop members, one stop member (74 or 76) may be utilized incombination with a body 72 having a smaller cross-sectional areaproximate the stop member and a larger cross-sectional area to providefor, in effect, a second stop with the body 72. The body may be solid ormay contain a lumen over a length thereof, the lumen being defined by awall having one or more openings therein for release of a bio-activeagent from the lumen. The body 72 has a retrieval member 78 positionedat a proximal end thereof, the retrieval member 78 either being attachedto the body 72 or formed thereon. In one embodiment, a second retrievalmember is positioned at a distal end of the body 72 and a second set ofappendages are spaced from the appendages 82, limited in movement alongthe body by third and fourth stop members.

This invention has been described and specific examples of the inventionhave been portrayed. While the invention has been described in terms ofparticular variations and illustrative figures, those of ordinary skillin the art will recognize that the invention is not limited to thevariations or figures described. In addition, where methods and stepsdescribed above indicate certain events occurring in certain order,those of ordinary skill in the art will recognize that the ordering ofcertain steps may be modified and that such modifications are inaccordance with the variations of the invention. Additionally, certainof the steps may be performed concurrently in a parallel process whenpossible, as well as performed sequentially as described above.Therefore, to the extent there are variations of the invention, whichare within the spirit of the disclosure or equivalent to the inventionsfound in the claims, it is the intent that this patent will cover thosevariations as well. Finally, all publications and patent applicationscited in this specification are herein incorporated by reference intheir entirety as if each individual publication or patent applicationwere specifically and individually put forth herein.

1. A filter for placement in a blood vessel, the filter comprising: abody defining a longitudinal axis, the body having a generally planarsurface extending generally parallel to the longitudinal axis; and aplurality of appendages extending away from the longitudinal axis, atleast one of the plurality of appendages having a generally planarsurface.
 2. The filter of claim 1, wherein the at least one of theplurality of appendages comprises a cross-section selected from a groupconsisting essentially of generally rectangular and squarecross-sections and combinations thereof.
 3. The filter of claim 2,wherein each of the plurality of appendages comprise a cross-sectionselected from a group consisting essentially of generally rectangularand square cross-sections, and combinations thereof.
 4. The filter ofclaim 3, wherein at least one of the appendages comprises an anchormember.
 5. (canceled)
 6. A filter, comprising: a longitudinal bodyincluding a proximal section having a first cross-sectional area, adistal section having a second cross-sectional area, and a joiningsection positioned between the proximal and distal sections having athird cross-sectional area less than both the first and secondcross-sectional areas; and a plurality of appendages having a proximalend joined to a hub such that the appendages in a non-stressed positionlie in a plane generally oblique to the longitudinal body, the hubincluding an opening configured for movement along a length of thejoining section.
 7. The filter according to claim 6, wherein theproximal section and distal section of the body are generally tubular.8. The filter according to claim 7, wherein the first cross-sectionalarea is approximately equivalent to the second cross-sectional area. 9.The filter according to claim 7, wherein the joining section isgenerally tubular, and wherein the opening has a diameter less than thediameter of the proximal section and distal section.
 10. The filteraccording to claim 6, wherein the joining section has a length betweenapproximately 0.5 mm and approximately 40 mm.
 11. The filter accordingto claim 6, wherein at least one of the proximal section and distalsection have a non-circular cross-sectional shape.
 12. The filteraccording to claim 6, wherein the appendages are formed from a singlesheet of material having a thickness between approximately 0.1 mm andapproximately 0.4 mm.
 13. (canceled)
 14. The filter according to claim12, wherein the sheet comprises a material selected from the groupconsisting essentially of stainless steel, shape memory metals, shapememory alloys, shape memory metal alloys, metal alloys, linear elasticshape memory alloy, shape memory polymers, polymers, bio-resorbablematerials and combinations thereof.
 15. (canceled)
 16. The filteraccording to claim 6, wherein one or more of the appendages includes awidth that decreases in a direction away from the body. 17-19.(canceled)
 20. The filter according to claim 6, further comprising aretrieval member connected to the proximal section of the body.
 21. Thefilter according to claim 6, wherein the appendages are stressed in agenerally curved configuration to extend generally in either a proximalor distal direction.
 22. The filter according to claim 6, wherein atleast a portion of the body includes a length with a lumen, a wall ofthe body along the length of the lumen including a plurality of pores influid communication with the lumen. 23-36. (canceled)
 37. A filter,comprising: a longitudinal body including a proximal section, anintermediate section, and a distal section; a first joining sectionpositioned between the proximal section and the intermediate section anda second joining section positioned between the intermediate section andthe distal section, the first and second joining sections each having across-sectional area less than a cross-sectional area of the proximalsection, the intermediate section and the distal section; a first set ofappendages having a proximal end joined to a first hub such that theappendages in a non-stressed position lie in a plane generally obliqueto the longitudinal body, the first hub positioned along the firstjoining section and including an opening configured for movement along alength of the first joining section; and a second set of appendageshaving a proximal end joined to a second hub such that the appendages ina non-stressed position lie in a plane generally oblique to thelongitudinal body, the second hub positioned along the second joiningsection and including an opening configured for movement along a lengthof the second joining section.
 38. The filter according to claim 37,wherein the proximal section, the intermediate section, and the distalsection are generally tubular.
 39. The filter according to claim 38,wherein the first and second joining sections are generally tubular, andwherein the openings thereof have a diameter less than the diameter ofthe proximal section, intermediate section and distal section.
 40. Thefilter according to claim 37, wherein the first and second joiningsections have a length between approximately 0.5 mm and approximately 40mm. 41-66. (canceled)